After reading the January 1975 issue of Popular Electronics that demonstrated the Altair 8800, Gates contacted MITS (Micro Instrumentation and Telemetry Systems), the creators of the new microcomputer, to inform them that he and others were working on a BASIC interpreter for the platform. In reality, Gates and Allen did not have an Altair and had not written code for it; they merely wanted to gauge MITS's interest. MITS president Ed Roberts agreed to meet them for a demo, and over the course of a few weeks they developed an Altair emulator that ran on a minicomputer, and then the BASIC interpreter. The demonstration, held at MITS's offices in Albuquerque, was a success and resulted in a deal with MITS to distribute the interpreter as Altair BASIC. Paul Allen was hired into MITS, and Gates took a leave of absence from Harvard to work with Allen at MITS, dubbing their partnership "Micro-soft" in November 1975. Within a year, the hyphen was dropped, and on November 26, 1976, the tradename "Microsoft" was registered with the USPTO.
Microsoft's BASIC was popular with computer hobbyists, but Gates discovered that a pre-market copy had leaked into the community and was being widely copied and distributed. In February 1976, Gates wrote an Open Letter to Hobbyists in the MITS newsletter saying that MITS could not continue to produce, distribute, and maintain high-quality software without payment. This letter was unpopular with many computer hobbyists, but Gates persisted in his belief that software developers should be able to demand payment. Microsoft became independent of MITS in late 1976, and it continued to develop programming language software for various systems.
According to Gates, people at Microsoft often did more than one job during the early years; whoever answered the phone when an order came in was responsible for packing and mailing it. Gates oversaw the business details, but continued to write code as well. In the first five years, he personally reviewed every line of code the company shipped, and often rewrote parts of it as he saw fit.
IBM partnership
In 1980 IBM approached Microsoft to make the BASIC interpreter for its upcoming personal computer, the IBM PC. When IBM's representatives mentioned that they needed an operating system, Gates referred them to Digital Research (DRI), makers of the widely used CP/M operating system. IBM's discussions with Digital Research went poorly, and they did not reach a licensing agreement. IBM representative Jack Sams mentioned the licensing difficulties during a subsequent meeting with Gates and told him to get an acceptable operating system. A few weeks later Gates proposed using 86-DOS (QDOS), an operating system similar to CP/M and which Tim Paterson of Seattle Computer Products had made for hardware similar to the PC. Microsoft made a deal with SCP to become the exclusive licensing agent, and later the full owner, of 86-DOS, but did not mention that IBM was a potential customer. Gates never understood why DRI had walked away from the deal, and in later years he claimed that DRI founder Gary Kildall capriciously "went flying" during an IBM appointment, a characterization that Kildall and other DRI employees would deny. After adapting the operating system for the PC, Microsoft delivered it to IBM as PC-DOS in exchange for a one-time fee, but retained the copyright so that it could sell the system to other hardware vendors.
As several companies reverse-engineered the IBM architecture and developed clones Microsoft was quick to license DOS to other manufacturers, calling it MS-DOS (for Microsoft Disk Operating System). By marketing MS-DOS aggressively to manufacturers of IBM-PC clones and by virtue of its undivided ownership of the operating system's source code, Microsoft went from a small player to one of the major software vendors in the home computer industry. Microsoft continued to develop operating systems as well as software applications.
